Two-Layer Generation Expansion Planning Based on Flexibility Balance

Reasonable planning of flexible power sources is crucial for the reliable operation of new power systems based on new energy sources. However, in the long-term planning, how to consider the short-term ramping capability of the flexible power supply to meet the capacity demand of the net load and the flexible ramping requirement at the same time is still an unsolved problem. Therefore, this paper conducts research on generation expansion planning based on flexibility balance. Firstly, the flexibility balance are modeled based on the flexible supply domain and the net load fluctuation domain, which are used as the flexible supply and demand constraints in the planning stage. Then, a two-layer expansion planning model is constructed, including two modules of investment decision and production simulation. Flexibility index is proposed to quantify the system’s ability to adjust at different levels of payload, and incorporated into the planning model for iterative optimization. Finally, an example is verified on the improved IEEE-39 node system. The test results show that the long-term generation expansion planning scheme based on the balance of flexible supply and demand can effectively meet the net load demand and its ramping demand.